/*
 * Copyright (C) 2020 Graylog, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the Server Side Public License, version 1,
 * as published by MongoDB, Inc.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * Server Side Public License for more details.
 *
 * You should have received a copy of the Server Side Public License
 * along with this program. If not, see
 * <http://www.mongodb.com/licensing/server-side-public-license>.
 */
package org.graylog2.inputs.extractors;

import org.graylog2.ConfigurationException;
import org.graylog2.plugin.Message;
import org.graylog2.plugin.MessageFactory;
import org.graylog2.plugin.TestMessageFactory;
import org.graylog2.plugin.Tools;
import org.graylog2.plugin.inputs.Extractor;
import org.junit.jupiter.api.Test;

import java.util.Collections;
import java.util.Map;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;

public class RegexExtractorTest extends AbstractExtractorTest {
    private final MessageFactory messageFactory = new TestMessageFactory();

    @Test
    public void testBasicExtraction() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.COPY, "somefield", "our_result", config("id:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        assertNotNull(msg.getField("our_result"));
        assertEquals("<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001", msg.getField("somefield"));
        assertEquals("9001", msg.getField("our_result"));
    }

    @Test
    public void testBasicExtractionWithCutStrategy() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "somefield", "our_result", config("id:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        assertNotNull(msg.getField("our_result"));
        assertEquals("<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:", msg.getField("somefield"));
        assertEquals("9001", msg.getField("our_result"));
    }

    @Test
    public void testBasicExtractionWithCutStrategyCanOverwriteSameField() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "message", "message", config("The (.+)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        assertEquals("short message", msg.getField("message"));
    }

    @Test
    public void testBasicExtractionDoesNotFailOnNonMatch() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.COPY, "somefield", "our_result", config("nothing:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        assertNull(msg.getField("our_result"));
        assertEquals("<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001", msg.getField("somefield"));
    }

    @Test
    public void testBasicExtractionDoesNotFailOnNonMatchWithCutStrategy() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "somefield", "our_result", config("nothing:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        assertNull(msg.getField("our_result"));
        assertEquals("<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001", msg.getField("somefield"));
    }

    @Test
    public void testExtractsFirstMatcherGroupWhenProvidedWithSeveral() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001 lolwut");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.COPY, "somefield", "our_result", config("id:(\\d+).*(lolwut)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        assertNotNull(msg.getField("our_result"));
        assertEquals("<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001 lolwut", msg.getField("somefield"));
        assertEquals("9001", msg.getField("our_result"));
    }

    @Test
    public void testDoesNotFailOnNonExistentSourceField() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "LOLIDONTEXIST", "our_result", config("id:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);
    }

    @Test
    public void testDoesNotFailOnSourceFieldThatIsNotOfTypeString() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", 9001);

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "somefield", "our_result", config("id:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);
    }

    @Test
    public void testBasicExtractionWithCutStrategyDoesNotLeaveEmptyFields() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "somefield", "our_result", config("(.*)"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        assertNotNull(msg.getField("our_result"));
        assertEquals("fullyCutByExtractor", msg.getField("somefield"));
    }

    @Test
    public void testDoesNotInitializeOnNullConfigMap() throws Exception {
        assertThrows(ConfigurationException.class, () -> {
            new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "somefield", "somefield", null, "foo", noConverters(), Extractor.ConditionType.NONE, null);
        });
    }

    @Test
    public void testDoesNotInitializeOnNullRegexValue() throws Exception {
        assertThrows(ConfigurationException.class, () -> {
            new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "somefield", "somefield", config(null), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        });
    }

    @Test
    public void testDoesNotInitializeOnEmptyRegexValue() throws Exception {
        assertThrows(ConfigurationException.class, () -> {
            new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "somefield", "somefield", config(""), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        });
    }

    @Test
    public void testDoesNotRunWhenRegexConditionFails() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.COPY, "somefield", "our_result", config("id:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.REGEX, "^XXX");
        x.runExtractor(msg);

        assertNull(msg.getField("our_result"));
        assertEquals("<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001", msg.getField("somefield"));
    }

    @Test
    public void testDoesNotRunWhenStringConditionFails() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        msg.addField("somefield", "<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001");

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.COPY, "somefield", "our_result", config("id:(\\d+)"), "foo", noConverters(), Extractor.ConditionType.STRING, "FOOBAR");
        x.runExtractor(msg);

        assertNull(msg.getField("our_result"));
        assertEquals("<10> 07 Aug 2013 somesubsystem: this is my message for username9001 id:9001", msg.getField("somefield"));
    }

    @Test
    public void testDoesNotCutFromStandardFields() throws Exception {
        Message msg = messageFactory.createMessage("The short message", "TestUnit", Tools.nowUTC());

        RegexExtractor x = new RegexExtractor(metricRegistry, "foo", "foo", 0, Extractor.CursorStrategy.CUT, "message", "our_result", config("^(The).+"), "foo", noConverters(), Extractor.ConditionType.NONE, null);
        x.runExtractor(msg);

        // Would be cut to "short message" if cutting from standard field was allowed.
        assertEquals("The short message", msg.getField("message"));
    }

    public static Map<String, Object> config(final String regex) {
        return Collections.singletonMap("regex_value", regex);
    }
}
